Apparatus and system for navigating in GPS denied environments

ABSTRACT

An apparatus and system for allowing accurate navigation to a target regardless of GPS jamming levels. An apparatus and system can be used to update the navigation solution based upon seeker measurements in at least one of three electromagnetic frequency domains: infrared, visible, and radio frequency (RF).

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application, claiming the benefit of, parentapplication Ser. No. 12/726,025 filed on Mar. 17, 2010 now U.S. Pat. No.8,412,450, whereby the entire disclosure of which is incorporated herebyreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The invention described herein may be manufactured and used by or forthe government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

FIELD OF THE INVENTION

The invention generally relates to an apparatus and system for allowingaccurate navigation to a target regardless of GPS jamming levels.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a drawing of an embodiment of a system in accordance with theprinciples of the invention.

It is to be understood that the foregoing and the following detaileddescription are exemplary and explanatory only and are not to be viewedas being restrictive of the invention, as claimed. Further advantages ofthis invention will be apparent after a review of the following detaileddescription of the disclosed embodiments, which are illustratedschematically in the accompanying drawing and in the appended claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Embodiments of the invention generally relate to an apparatus and system100 for allowing accurate navigation to a target regardless of GPSjamming 22 levels. Additionally, embodiments of the invention provide anapparatus and system to update the navigation solution based upon seekermeasurements in at least one of three electromagnetic frequency domains:infrared, visible, and radio frequency (RF). At least three markers(including a marker substance) are deployed (creating a mark 2, 4, 6,and 8 of FIG. 1) no farther from the target 12 than the distance atwhich the capability of the inertial navigation system and thecapability of the seeker allow the object being navigated 10 to benavigated/guided to the target 12.

Embodiments of the invention include a marker having a marker substance.The marker substance is a substance (which can be a solid matter, suchas, for example, a powder, liquid matter, something in between,including as a gelatinous matter) that has, but is not limited to, atleast one of the following: 1) an exothermic material which glows in theinfrared (IR); 2) a bright day-glow color detectable by an electro-opticseeker; and 3) a radio frequency ID (RFID) or a material which reflects,or responds to, radio frequency or millimeter wave signals. In oneembodiment, the substance includes paint-like material having at leastone of an exothermic material which glows in the infrared (IR), a brightday-glow color detectable by an electro-optic seeker, a radio frequencyID (RFID) or a material which reflects, or responds to, radio frequencyor millimeter wave signals.

The marker substance is housed in a container and is dispersed from anaerial vehicle including as a Joint Standoff Weapon (JSOW).

The material that houses the marker substance and that is dispersed froman aerial vehicle is any material that ruptures in response to contactassociated with the material landing at its destination, therebyreleasing the marker substance and creating a mark (2, 4, 6, and 8 ofFIG. 1). In one embodiment, the material that houses the markersubstance is a balloon type material.

In another embodiment, the marker substance is housed in a container anddispersed using a gas when the marker lands at its destination.

Radio Frequency Identification (RFID) tags provide a method of remotelystoring and retrieving data using a small object attached to orincorporated into a substance. RFID tags enable data to be transmittedvia a portable device called a tag, read by a reader, and processedaccording to the needs of the particular application.

In embodiments, transmitted data provides information that can be usedto determine the location of the object being navigated relative to thetarget. Data can be printed or etched on an electronic substrate andthen embedded in a plastic or laminated paper tag.

Tags are classified according to their radio frequency: low-frequency,high frequency, UHF and microwave. Low-frequency tags are commonly usedin automobile anti-theft systems and animal identification.High-frequency tags are used in library books, pallet tracking, buildingaccess, airline baggage tracking, and apparel tracking. Low- andhigh-frequency tags can be used without a license. UHF tags are alsoused to track pallets, containers, trucks, and trailers. UHF cannot beused globally as there is no one global standard. Microwave tags areused in long-range access.

Also, tags may be either passive or active. Passive tags do not havetheir own power supply. Their power comes from a minute electricalcurrent induced by an incoming radio-frequency scan. Active tags havetheir own power source. The lack of a power source makes the passive tagmuch less expensive to manufacture and much smaller (thinner than asheet of paper) than an active tag. As a result, the vast majority ofRFID tags are passive. However, the response of a passive tag istypically just an ID number. Active tags have longer ranges, the abilityto store more information, and are more accurate and reliable.

The tag includes a transponder with a digital memory chip with a uniqueelectronic product code. A stationary or handheld device called aninterrogator, having an antenna, transceiver, and decoder, emits asignal creating an electromagnetic zone. When a tag comes within therange of a seeker, it detects an activation signal that causes the tagto activate and start sending data. The seeker captures the data encodedin the tag's integrated circuit, decodes it, and uses it for processinginformation to enable the weapon to guide to the desired target.

The object being navigated 10 includes a single, dual, or tri-modeseeker. For purposes of illustration, an object being navigated 10 isillustrated as having tri-mode seeker capability; however, a single,dual, or tri-mode seeker can be used in accordance with the principlesof the invention. An object being navigated that has a single modeseeker is capable of one of the following: 1) passively detectinginfrared via an infrared seeker 26; 2) passively detect Electro-opticsignals via an Electro-optic seeker 28; and 3) detect (and, in someembodiments, actively emitting) radio frequency or millimeter wavesignals via a radio frequency (RF) seeker 24. An object being navigatedthat has a dual-mode seeker is capable of two of the following: 1)passively detecting infrared via an infrared seeker 26; 2) passivelydetecting Electro-optic signals via an Electro-optic seeker 28; and 3)detecting (and, in some embodiments, actively emitting) radio frequencyor millimeter wave signals via a radio frequency (RF) seeker 24. Anobject being navigated that has tri-mode seeker is capable of all of thefollowing: 1) passively detecting infrared via an infrared seeker 26; 2)passively detecting Electro-optic signals via an Electro-optic seeker28; and 3) detecting (and, in some embodiments, actively emitting) radiofrequency or millimeter wave signals via a radio frequency (RF) seeker24.

Once the marker has landed, ruptured, and the marker substance has beenreleased, (thereby creating a mark 2, 4, 6, and 8 of FIG. 1), thelocation of a target(s) 12 can be identified as follows.

In embodiments, a satellite 14 recognizes/identifies the pattern andlocation of the marks (2, 4, 6, and 8 of FIG. 1) by detecting at leastthree of the marks (2, 4, 6, and 8 of FIG. 1) and/or a signalcommunicated by at least three of the marks (2, 4, 6, and 8 of FIG. 1);the satellite 14 also communicates the location of the target 12 to theobject being navigated 10 via a data link 16 from the satellite 14 tothe object being navigated 10. The object being navigated 10receives/detects at least one signal (in any one, two, orthree—depending on the embodiment—of the three signal frequencies) fromat least three of the marks (2, 4, 6, and 8 of FIG. 1) via the single,dual, or tri-mode seeker on the object being navigated 10 that allowsthe object being navigated 10 to actively calculate the angle, angularrates, ranges and/or range rates to the marks (2, 4, 6, and 8 of FIG. 1)(in any one two, or three—depending on the embodiment—of the threesignal frequencies). Using the calculated angle, angular rates, rangesand/or range rates to the marks and the information transmitted to theobject being navigated 10 (the location of the marks), the location ofthe object being navigated 10 can be determined and its navigationsolution updated. As the object being navigated 10 knows the location ofthe target 12 as well as its present location, the object beingnavigated 10 can then calculate a route to the target 12.

In another embodiment, an unmanned aerial vehicle (UAV) 18recognizes/identifies the pattern and location of the marks (2, 42 6,and 8 of FIG. 1) by detecting at least three of the marks (2, 4, 6, and8 of FIG. 1) and/or a signal communicated by at least three of the marks(2, 4, 6, and 8 of FIG. 1); the UAV 18 also communicates the location ofthe target 12 to the object being navigated 10 via a data link 20 fromthe UAV 18 to the object being navigated 10. The object being navigated10 receives/detects at least one signal (in any one, two, orthree—depending on the embodiment—of the three signal frequencies) fromat least three of the marks (2, 4, 6, and 8 of FIG. 1) via the single,dual, or tri-mode seeker on the object being navigated 10 that allowsthe object being navigated 10 to actively calculate the angle, angularrates, ranges and/or range rates to the marks (2, 4, 6, and 8 of FIG.1). Using the calculated angle, angular rates, ranges and/or range ratesto the marks and the information transmitted to the object beingnavigated 10 (the location of the marks (2, 4, 6, and 8 of FIG. 1)), thelocation of the object being navigated 10 can be determined and itsnavigation solution updated. As the object being navigated 10 knows thelocation of the target 12 as well as its present location, the objectbeing navigated 10 can then calculate a route to the target 12.

In another embodiment, the a priori geo-locations of the marks are knownby the object being navigated 10 (loaded onto the object being navigated10). The object being navigated 10 receives/detects a signal (in anyone, two, or three—depending on the embodiment—of the three signalfrequencies) from each of the marks (2, 4, 6, and 8 of FIG. 1) via thesingle, dual, or tri-mode seeker on the object being navigated 10 thatallows the object being navigated 10 to actively calculate the angle,angular rates, ranges and/or range rates to the marks (2, 4, 6, and 8 ofFIG. 1). Using the calculated angle, angular rates, ranges and/or rangerates to the marks and the information transmitted to the object beingnavigated 10 (the location of the marks (2, 4, 6, and 8 of FIG. 1)), thelocation of the object being navigated 10 can be determined and itsnavigation solution updated. As the object being navigated 10 knows thelocation of the target 12 as well as its present location, the objectbeing navigated 10 can then calculate a route to the target 12.

Various permutations are possible depending in part on:

-   -   1) the characteristics of the marker (marker substance and        mark), i.e., which of the following is used/included in the        marker (marker substance and mark):        -   a) an exothermic material which glows in the infrared (IR);        -   b) a bright day-glow color detectable by an electro-optic            seeker; and        -   c) a radio frequency ID (RFID) or a material which reflects,            or responds to, radio frequency or millimeter wave signals;    -   2) the capability of the object being navigated to detect the        frequency(ies) of the marks, i.e., whether the object being        navigated has a single, dual, or tri-mode seeker;    -   3) the circumstances presented by the situation the method is        practiced in (for example, even if all three frequencies are        covered in the marker (marker substance and mark), and the        object being navigated has a tri-mode seeker, it is possible        that only one or two of the frequencies can be identified for        whatever reason; therefore, only one or two of the frequencies        will be used to update a navigation solution);    -   4) what detects the location of the mark, i.e., satellite, UAV,        and how that is communicated to the object being navigated 10.        A person having ordinary skill in the art will recognize that        the permutations claimed in the claims as originally filed are        not the only possible permutations based on the Detailed        Description.

While the invention has been described, disclosed, illustrated and shownin various terms of certain embodiments or modifications which it haspresumed in practice, the scope of the invention is not intended to be,nor should it be deemed to be, limited thereby and such othermodifications or embodiments as may be suggested by the teachings hereinare particularly reserved especially as they fall within the breadth andscope of the claims here appended.

The invention claimed is:
 1. A system for guiding an object to a target in a GPS denied environment, comprising: an infrared seeker associated with said object; an electro-optic seeker associated with said object; a radio frequency seeker associated with said object; an RFID tag configured to respond to at least one millimeter wave signal; a plurality of markers, each of said plurality of markers being a product having said RFID tag integrated therein, each of said plurality of markers also having an exothermic material being detectable in the infrared electromagnetic frequency and at least one material in the visible electromagnetic frequency detectable by said electro-optic seeker; an aerial vehicle configured to determine a location of at least three of said plurality of markers in relation to said target by detecting through image processing said exothermic material and said material in the visible electromagnetic frequency, said aerial vehicle configured to communicate said location of said at least three of said plurality of markers in relation to said target to said object; said object being configured to calculate an angle to each of said at least three of said plurality of markers using passively detected signals from said exothermic material detected via said infrared seeker, passively detected electro-optic signals detected via said electro-optic seeker, and data from detected radio frequency signals detected via said radio frequency seeker; and said object being configured to determine a location of said object in relation to said target using said calculated angle to each of said at least three of said plurality of markers and said communicated location of said at least three of said plurality of markers in relation to said target without use of GPS information. 